PEDIATRIC EKG WORKSHOP - PDF Free Download

WHAT s NEW IN MEDICINE 2018 PEDIATRIC EKG WORKSHOP Salaam Sallaam, MD Asst. Prof, Division of Cardiology Department of Pediatrics Seattle Children s Hospital

OVERVIEW Pediatric EKG interpretation Normal variants Pediatric Tachyarrhythmias Pediatric Bradycardias Miscellaneous

Cardiac Conduction System

Pediatric EKG Interpretation - Get familiar with the EKG machine - Be organized and methodical - Look at EVERY EKG the same way, no matter how abnormal it appears - Describe findings - Think of differential diagnosis of each abnormal finding - Integrate EKG with history, PE, and other patient data to formulate diagnosis

Technique The 12 lead EKG includes recordings from: Standard bipolar leads I, II and III Augmented leads avf, avl and avr Standard unipolar precordial leads V1 to V6 In a 15 lead EKG: The right-sided leads V3R, V4R and V7 are recorded additionally In addition, a longer recording of a single lead (usually lead II) is obtained to analyze the rhythm more precisely Lead II is chosen for most EKG interval measurements, as it is parallel to the long axis of the heart

V1: Fourth intercostal space to the right of the sternum. V2: Fourth intercostal space to the Left of the sternum. V3: Directly between leads V2 and V4. V4: Fifth intercostal space at midclavicular line. V5: Level with V4 at left anterior axillary line. V6: Level with V5 at left midaxillary line. (Directly under the midpoint of the armpit)

IMPORTANT POINTS TO CONSIDER o Was EKG properly obtained? Correct lead placement Normal paper speed (25 mm per second) Appropriate sensitivity full standard 1mV = 10 mm deflection limb and chest leads may NOT be the same standard o How old is the patient? Normals are age dependent

QRS Standardization 1 millivolt PR QT interval Full Half 0.2 secs

Basic EKG

EKG ANALYSIS Rhythm Rate Axis Morphology Intervals Hypertrophy

Rhythm Sinus rhythm = sinus node - AV node Atrial rhythm Left atrium - AV node Low right atrium - AV node P wave axis (leads I and avf) 0 - +90 = sinus rhythm +90-180 = left atrial rhythm 0 - -90 = low right atrial rhythm

Rhythm assessment contd. SA node RA LA -90 (+) I (-) avf 180 0 (I) LV (-) I (+) avf RV (+) I (+) avf (avf) +90

Rhythm assessment (contd) No P waves junctional or idioventricular rhythm atrial fibrillation Multiple P waves (for each QRS) atrial flutter 2 nd or 3 rd degree AV block P waves of different shapes wandering atrial pacemaker PAC s

EKG ANALYSIS Rhythm Rate Axis Morphology Intervals Hypertrophy

Heart Rate Using a normal paper speed of 25 mm/second, Each small box on the EKG = 1 mm or 0.04 seconds. Each large box, or 5 mm, = 0.20 seconds.

Calculating Heart Rate Method 1: Count the number of small squares between the R-R intervals and divide 1500 by the number of small squares Method 2: Count the number of large squares between the R-R intervals and divide 300 by the number of large squares

Calculating Heart Rate Method 3: Count and multiply the number of QRS complexes on the 12 lead ECG paper by 6 to obtain the heart rate (it takes 10 secs to record an EKG). Method 4: Memorize heart rate for selected RR intervals (300-150-100-75-60-50) Start 300 150 100 75 60 50 43

Sinus Arrhythmia

EKG ANALYSIS Rhythm Rate Axis Morphology Intervals Hypertrophy

Axis determination Leads I and avf are normally used to determine the QRS axis. Normal axis: Positive QRS in leads I and avf. Left axis deviation: Positive QRS in lead I and negative QRS in lead avf. Right axis deviation: Negative QRS in lead I and a positive QRS in lead avf. Indeterminate axis: Negative QRS in lead I and avf, also referred to as extreme RAD.

I avf 270 I avf 180 0 I avf 90 I avf

EKG ANALYSIS Rhythm Rate Axis Morphology Intervals Hypertrophy

Morphology P - axis - amplitude - duration

Axis Amplitude lead II (if NSR) normal < 3 mm Morphology > 3 mm lead II = right atrial enlargement uration lead V 1 normal < 0.1 sec (2.5 small boxes) > 0.1 sec or broad/notched P waves in lead V 1 = left atrial enlargement

RA enlargement LA enlargement

Morphology R - axis - amplitude - duration Q S

QRS axis (contd) I avf (-)90 0 (+)90 180 0 (+)90 (-)90 0 (-) 90 180 0 (+)90 (+)90 180 180 (-)90 0 (+)90 (-)90 180 (-)90 180 0 (+)90

QRS axis -90 Age specific normals RA LA 180 0 (I) LV RV 3 yr Newborn (avf) +90 1 mo

QRS axis Right axis deviation RVH Right bundle branch block Left axis deviation Endocardial cushion defect Tricuspid atresia LVH (volume overload) Left bundle branch block

Right axis deviation

Left axis deviation

QRS Amplitude o Normals by age and lead (R & S waves) o > ULN indicates ventricular hypertrophy cannot use if bundle branch block present o Low voltage (limb leads < 5 mm) Myocarditis Pericarditis/pericardial effusion Hypothyroidism Thick chest wall

Left ventricular hypertrophy

Right Ventricular hypertrophy

QRS Duration o Time required for ventricular depolarization o General, <0.08 sec (2 small boxes) o Prolonged = abnormal delay or spread of impulse through ventricles Bundle branch blocks (R & L) Interventricular conduction delay Ventricular rhythm/ arrhythmias Ventricular pacemaker

Q waves o Ventricular septal depolarization o Present in leads II, III, avf, V 5, and V 6 o Normal amplitude < 5 mm o Normal duration < 0.02 sec o Deep and wide Infarction Fibrosis

Morphology T - axis - amplitude - duration

T waves o Ventricular repolarization o Usually mirrors QRS o Lead V 1 very important variable from birth to 5 days (+ is OK) negative until adolescence strong indicator of RVH and ventricular strain pattern if abnormal

T waves o Tall, peaked T waves Hyperkalemia LVH/volume overload o Flat T waves Non-specific Hypokalemia Hypothyroidism Pericarditis, myocarditis, ischemia LVH/pressure overload

EKG ANALYSIS Rhythm Rate Axis Morphology Intervals Hypertrophy

Intervals PR interval R P Q PQ S PR

PR interval o Impulse delay in AV node o Age specific normals o Prolonged PR (1 st degree AV block) abnormal AV node conduction myocarditis, toxins, metabolic derangement, congenital heart disease, medications, normal variant o Short PR WPW (delta wave) enhanced AVN conduction

ST segment R T J-point Q S ST

ST segment o Horizontal, isoelectric o 1-2 mm elevation/depression is not necessarily abnormal o J-point Depression Elevation or early repolarization o Abnormal ST shifts abnormal T waves downward sloping ST segment horizontal ST segment for >0.08 sec

ST segment J-point T T T J-point depression ST depression Early repolarization

ST segment o Pathologic ST changes Pericardial disease Myocarditis Myocardial ischemia/infarction Electrolyte abnormalities hypocalcemia prolongs ST segment (and QTc) hypercalcemia shortens ST segment

QT interval o Time required for ventricular depolarization and repolarization o Varies with heart rate o QTc = QT/ RR Normal < 0.45, up to 0.49 in infants o Prolonged QTc Hypocalcemia Myocarditis, myocardial disease Long QT syndrome

Summary o Keep in mind the reason for EKG o Look at every tracing the same way o Patient age o Calibration ( standard ) o Rhythm o Rate o Systematic, left-to-right inspection of EKG

OVERVIEW Pediatric EKG interpretation Normal variants Pediatric Tachyarrhythmias Pediatric Bradycardias Miscellaneous

Introduction o Rhythm disturbances in children Primary Secondary Associated with cardiac disease o The major risk of any arrhythmia is decreased cardiac output or degeneration into more critical arrhythmia, leading to syncope or death o Therefore it is important to determine the potential for any arrhythmia to degenerate into critical arrhythmia

General Principles o Symptoms may vary depending on the age o Recording of a suspected arrhythmia is necessary before diagnosing or treating a suspected arrhythmia o The urgency of work up and treatment depends on Symptom severity Cardiac structure & function Activity profile of a patient o P/E most often may be entirely normal

General Principles In evaluating a patient with arrhythmia associated with hemodynamic compromise, THINK SIMPLE. Fast/ disorganized: cardioversion/ defibrillation Slow: CPR

OVERVIEW Pediatric EKG interpretation Normal variants Pediatric Tachyarrhythmias Pediatric Bradycardias Miscellaneous

Normal Variants Recognition of normal variants is important to allay anxiety and to avoid unnecessary investigations Sinus arrhythmia: Phasic variations in heart rate with inspiratory acceleration and expiratory deceleration

Wandering atrial pacemaker: Characterized by different P wave morphologies on the same EKG Related to alterations in vagal tone Wenckebach phenomena: Progressive lengthening of PR interval followed by a dropped beat. Related to alterations in vagal tone

Variations in heart rate: Sinus tachycardia: Has been documented at rates at 230-250 bpm Always look for a secondary cause Differentiated from SVT: variations with activity/ crying, and presence of secondary cause Sinus bradycardia: Sinus rate below expected for patient s age A highly conditioned athlete may have resting heart rate less than 40 bpm Be careful to rule out other causes like increased intracranial pressure, eating disorders, gastric distension, pharyngeal stimulation, toxins and drugs

Early Repolarization: - J-point elevation (of no more than 3 mm) with an upwardly concave ST segment - ST-segment elevation is more frequent in chest leads but can occur in leads I and II - Prevalent in young, African American males - Can be affected by exercise and hyperventilation

OVERVIEW Pediatric EKG interpretation Normal variants Pediatric Tachyarrhythmias Pediatric Bradycardias Miscellaneous

Evaluation of a child with an arrhythmia History: Accurate description may vary with age Important questions to ask: - How frequently and for how long do these episodes occur? - How does it begin and terminate? - What, if anything, initiates the episodes? - What, if anything, terminates the episodes? - History of caffeine intake, or any other meds? - In infants, enquire for symptoms of heart failure

Evaluation of a child with an arrhythmia Physical Examination: In setting of acute arrhythmia: - Check for signs of hemodynamic instability (suggested by evidence of poor cardiac output, hypotension, shock, altered mental status, and respiratory distress) In the setting of paroxysmal episodes: - Evaluate for any exacerbating factors e.g. fever, anemia, hyperthyroidism - Evaluate for any congenital heart defects that frequently are associated with arrhythmias - Evaluate for any infectious conditions

Diagnostic Testing EKG in sinus rhythm - Baseline rhythm - Conduction and repolarization intervals - Axes - Evidence of hypertrophy - Other abnormalities like pre-excitation, abnormal T wave morphology, etc EKG in arrhythmia accurate diagnosis Others: - Holter if daily symptoms - Event monitors (external or implantable) if more sporadic

Diagnostic Approach Three questions will define majority of the arrhythmias 1. Is the arrhythmia regular or irregular? 2. Are the QRS complexes narrow or wide? 3. What is the relationship between the P waves and the QRS complexes?

1. Is the arrhythmia regular or irregular? Regular Sinus tachycardia SVT Escape rhythms VT Irregular Sinus tachycardia Sinus arrhythmia Ectopic beats Advanced degree heart blocks AF/VF VT

2. Are the QRS complexes narrow or wide? Narrow QRS complexes: - Supraventricular - Junctional Wide QRS complexes: - Ventricular in origin - Paced complexes - Supraventricular if ass. with baseline BBB if ass. with rate dependent aberrancy if ass. with pre-excitation

3. What is the relationship between P waves and QRS complexes? 1:1 AV relationship: SVT Occ. VT > 1:1 AV relationship: Ectopic atrial tachycardia Multifocal atrial tachycardia Atrial flutter < 1:1 AV relationship: VT Junctional ectopic tachycardia

Narrow Complex Tachycardia - SVT

Wide Complex Tachycardia - VT

WPW syndrome

Atrial Flutter

Atrial fibrillation

Ectopic Atrial Tachycardia (with Variable Ventricular Response)

In pts with hemodynamic stable narrow complex tachycardia, adenosine can be diagnostic if not therapeutic.

Multifocal Atrial Tachycardia

Junctional Ectopic Tachycardia

Long QT syndrome

Torsade's de Pointes

OVERVIEW Pediatric EKG interpretation Normal variants Pediatric Tachyarrhythmias Pediatric Bradycardias Miscellaneous

The diagnostic possibilities of bradycardia are limited Sinus node dysfunction Clinical syndrome characterized by - Chronic SA nodal dysfunction - AV nodal conduction disturbances - Alternating bradycardia and tachycardia (the bradycardiatachycardia syndrome) - Commonly with underlying atrial fibrillation (AF) or atrial flutter

Heart blocks/ AV node dysfunction: Atrioventricular (AV) block is defined as a delay or interruption in the transmission of an atrial impulse to the ventricles due to an anatomical or functional impairment in the conduction system First-degree AV block occurs when the PR-interval is greater than the upper limits of normal for age. In general, the normal PR-intervals are: 70 to 170 msec in newborns, and 80 to 220 msec in young children and adults It reportedly occurs in up to 6 percent of normal neonates

Second-degree AV block, the organized atrial impulse fails to be conducted to the ventricle in a 1:1 ratio Mobitz type 1 block (Wenckebach phenomena): - There is progressive prolongation of the PR-interval until a P wave fails to be conducted. - Mobitz type 1 block is seen in normal children and young adults especially at times of high parasympathetic tone (e.g., sleep or in well-trained athletes) - It usually does not progress to complete block

Mobitz type 2 block: - The PR interval remains unchanged prior to the P wave that suddenly fails to conduct to the ventricles - It is associated with various forms of congenital heart disease and is seen after cardiac surgery. - Type 2 block occurs at or below the level of the AV node, indicating disease within the His bundle and bundle branches. - It has a less predictable course and frequently progresses to complete heart block

Third-degree AV block (Complete heart block): - There is complete failure of the atrial impulse to be conducted to the ventricles. - The atrial and ventricular activity are independent of one another. - The escape rhythm (usually slower than the lower limits of normal for age) is dictated by the location of the block - It can be either congenital or acquired

Miscellaneous

Acute Pericarditis

ALCAPA

HCMP with WPW

Pompe s disease

Dextrocardia

PAC s

PAC s Normally conducted PAC

PAC s Normally conducted PAC Blocked PAC

PAC s Normally conducted PAC Blocked PAC Aberrantly conducted PAC

PJC s

PVC s

Hyperkalemia

Hyperkalemia The earliest changes of hyperkalemia are - Appearance of peaked, narrow T waves - Shortened QT interval, which reflect abnormally rapid repolarization At a plasma K concentration 7 to 8 meq/l (changes due to delayed depolarization) - Widening of the QRS complex - Decreased amplitude with widening and eventual loss of the P wave, PR prolongation can also occur - Followed sometimes by second-degree or third-degree AV block Final changes - Sine-wave pattern, in which the widened QRS complex merges with the T wave - Followed by ventricular fibrillation or asystole

EKG changes with CNS Disease ECG abnormalities occur most often in patients with SAH, ischemic stroke, ICH, head trauma, neurosurgical procedures, acute meningitis, intracranial space-occupying tumors, and epilepsy The prevalence of EKG abnormalities in this group of patients varies from 50 to 90% Most common findings are depressed ST segments, flat or inverted T waves, prominent U waves, and prolongation of the QTc

Hypothermia EKG features of hypothermia - The Osborn wave, also known as the J wave, is a hump-like deflection between the QRS complex and the early part of the ST segment - Shivering artifacts due to muscular tremor - Sinus bradycardia - QRS prolongation, prolongation of the PR interval & QTc - Atrial fibrillation is common below 32 C - Risk of ventricular fibrillation is high below 28 C

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QUESTIONS

Pediatric Cardiology Board Review Book second edition QUESTION 1 A newborn presents with a narrow complex tachycardia. Adenosine is given, and the following rhythm strip was recorded. What is the most effective method for terminating the tachycardia? A. Cardioversion B. Oral propranolol C. Oral digoxin D. Intravenous amiodarone E. Oral amiodarone

QUESTION 2 A 16-year-old football player comes to you for evaluation of palpitations and dizziness. The following EKG was obtained. What would you do? A. Perform a 24-hour Holter monitor. If there are no arrhythmias, let him play B. Permanently disqualify him from all competitive sports based on the ECG C. Let him play as the ECG findings are a normal variant D. Not let him play until evaluation including an echocardiogram is performed E. Let him play and repeat the ECG in 6 months Pediatric Cardiology Board Review Book second edition

QUESTION 3 A 5-year-old child with diabetes ketoacidosis with a heart rate of 140 bpm. Serum potassium concentration is 8.5 mg/l. The ECG rhythm strip would be expected to demonstrate which of the following? A. Low amplitude T wave B. Prominent Q wave C. Prolonged QRS duration D. Short PR interval E. High amplitude P wave Pediatric Cardiology Board Review Book second edition

QUESTION 4 You would advise caution when using which of the following drugs in a patient with long QT syndrome (LQTS)? A. Lidocaine B. Amoxicillin with clavulanate C. Verapamil D. Erythromycin E. Metoprolol Pediatric Cardiology Board Review Book second edition

QUESTION 5 A 14-year-old previously healthy girl collapses while playing soccer. Following successful cardiopulmonary resuscitation, the following ECG was obtained. Which of the following is the most likely test to define her diagnosis? Pediatric Cardiology Board Review Book second edition

QUESTION 5 A 14-year-old previously healthy girl collapses while playing soccer. Following successful cardiopulmonary resuscitation, the following ECG was obtained. Which of the following is the most likely test to define her diagnosis? A. Cardiac MRI B. EP study C. Echocardiogram D. Genetic testing for KCNQ1 mutation Pediatric Cardiology Board Review Book second edition

QUESTION 6 An asymptomatic 14-year-old patient with a normal examination and resting ECG has a 24hour Holter monitor showing the finding in below. while sleeping. The rest of the Holter is normal. Which of the following is the next most appropriate step? Pediatric Cardiology Board Review Book second edition

QUESTION 6 An asymptomatic 14-year-old patient with a normal examination and resting ECG has a 24hour Holter monitor showing the finding below. while sleeping. The rest of the Holter is normal. Which of the following is the next most appropriate step? EP study B. Exercise treadmill test C. Reassurance D. Initiation of a β -blocker E. Pacemaker implantation Pediatric Cardiology Board Review Book second edition

QUESTION 7 A newborn baby presents with complete AV block. Which of the following is the most likely finding in the mother? A. Serum potassium of 8 B. Ventricular septal defect C. Low platelet count D. Positive rheumatoid factor E. Ro (SSA) and La (SSB) antibodies Pediatric Cardiology Board Review Book second edition